1. Field of the Invention
The present invention pertains to a large, self-contained and self-propelled oil recovery vessel and a method for recovering large quantities of oil or other floating pollutants such as would be encountered in a large-scale marine oil spill, well blow-out or pipeline rupture.
2. Background
The increasing reliance on marine transportation of large quantities of crude oil and other substances considered to be marine pollutants and the infrequent but damaging accidents involving oil tankers such as those experienced by the Torrey Canyon, the Amoco Cadiz and the Exxon Valdez have made clear the need for a large-scale oil recovery system. The sudden disgorgement of large quantities of crude oil into the open sea such as caused by the above-mentioned accidents and the well blow-outs or failures which have occasionally occurred around the world have made it apparent that conventional oil spill recovery equipment and methods are inadequate.
Several proposals for oil recovery vessels or ships have been disclosed in the prior art such as in U.S. Pat. Nos. 3,690,464 to Heinicke, 3,744,257 to Spanner, 3,847,816 to DePerna, 3,884,807 to Heddon, 3,929,644 to Fletcher, 3,966,615 to Petchul et al, 4,033,876 to Cocjin et al, 4,067,811 to Dallamore, 4,120,793 to Strain, 4,257,889 to Wober et al, 4,308,140 to Pierson, Jr., and 4,653,421 to Ayers et al. These patents disclose various systems, some of which are alleged to be capable of open sea recovery of floating oil. However, none of the systems disclosed in these patents are particularly adapted to receive, rapidly process and store large quantities of crude oil or a similar type pollutant floating on the surface of the open sea or a similar large body of water.
Several requirements for a large-scale oil recovery vessel have become evident from experience with previous marine oil spills such as the tanker accidents mentioned hereinabove. The recovery vessel must be capable of ingesting and processing large quantities of oil covered seawater wherein the oil layer may be up to several inches thick and while minimizing the intake of unpolluted water. The vessel must be capable of recovery of oil, debris and similar floating pollutants from the sea surface with minimal agitation or mixing of the pollutant material with sea water. Accordingly, the shipboard oil and water handling facilities should be arranged and constructed such that a minimal amount of mixing of water and oil occur. If this objective is not achieved, the oil separation and storage capacity is severely limited and the vessel must be frequently off-loaded to more capable separation equipment and larger storage facilities. The vessel must also be capable of temporarily storing large quantities of contaminated water to allow substantially complete separation of oil therefrom, and the vessel must store large quantities of separated oil so that operations of the vessel are not hindered by frequent excursions to a shore based pump-out station or interruption of recovery activities for lightering recovered oil to another storage vessel. Moreover, the vessel must be capable of recovering weathered as well as fresh oil equally well.
The shipboard water and oil handling capacity must be substantial so that large quantities of oil and water may be rapidly separated one from the other. Accordingly, the pumping capacity of the vessel must be adequate to ingest and move large quantities of oil covered water without affecting the trim or working draft of the vessel. Still further, the vessel must be capable of independent oil/water recovery and separation systems and processes in such a way that the different requirements of the systems do not compromise the effectiveness of each other.
Clearly, the length and breadth of the vessel must be substantial so that the vessel can operate in various sea states. Still further, the capital requirements for a vessel having the capabilities above mentioned are substantial and in this regard, and in accordance with the present invention, consideration should be given to the conversion of an existing ship such as a large crude oil carrier.
A review of the prior art mentioned above indicates that none of the references meet the desiderata mentioned herein nor, when viewed collectively, do they suggest the present invention which is summarized and described in detail hereinbelow.